TRANSCONA CENTENNIAL POOL REDEVELOPMENT – PHASE 1B 1

December 17, 2015 File No. 153928 City of Winnipeg Planning, Property & Development Department Municipal Accommodations Division Project Services Branch 4th floor, 185 King Street Winnipeg, MB. R3B 1J1 Attn: John Atkinson, Project Officer RE: Transcona Centennial Pool Redevelopment - Phase 1B Geotechnical Investigation As requested, Dyregrov Robinson Inc. (DRI) has undertaken a geotechnical investigation for Phase 1B of the Transcona Centennial Pool redevelopment project. The site is located at 1101 Wabasha Street in Winnipeg, Manitoba. The purpose of the investigation was to evaluate the subsurface conditions in order to provide foundation design recommendations that meet the requirements of the current Manitoba Building Code. The work was authorized by the City of Winnipeg on November 27, 2015 via P.O. Number 411964.

1) Proposed Pool Equipment Building

We understand that a single storey building will be constructed west of the outdoor pools to house pool related equipment. The new building will be about 330 m2 in size. A 9 m deep manhole / sump pit will be provided inside the building.

2) Field Investigation

On December 3, 2015, one test hole was drilled in the foot print of the proposed building; at the approximate location described on the test hole log. The test hole was drilled to auger refusal by Paddock Drilling Ltd. using a track mounted RM 30 drill rig equipped with 125 mm diameter solid stem augers. The test hole was backfilled with auger cuttings and bentonite chips.

The subsurface conditions were visually logged during drilling by DRI. Disturbed (auger cuttings) and undisturbed (Shelby tube) samples were recovered from the test hole and taken to our Soils Testing Laboratory for additional visual classification and testing. The laboratory testing consisted of determining moisture contents on all samples and measuring bulk unit weights and undrained shear strengths on the Shelby tube samples. The test hole log is attached and includes a description of the subsurface conditions encountered, results of the laboratory testing, and notes regarding the observations made during drilling.

DYREGROV ROBINSON INC.

101 - 1555 St. James Street Consulting Geotechnical Engineers

Winnipeg, MB R3H 1B5

TEL (204) 632-7252

FAX (204) 632-1442

TRANSCONA CENTENNIAL POOL REDEVELOPMENT – PHASE 1B 2

3) Subsurface Conditions

The soil stratigraphy encountered in the test holes, from site grade, consists of black silty clay, silt, silty clay and glacial till.

Black Silty Clay

Black silty clay was encountered at grade and is about 1.5 m thick. The clay contains trace organics and is stiff and moist. The clay has a moisture content around 40 percent.

Silt

A 150 m thick layer of silt was encountered below the black clay. It contains traces of clay, is brown in color and is loose and wet. The moisture content is around 25 percent.

Silty Clay

The usual thick deposit Lake Agassiz lacustrine silty clay was encountered beneath the silt at a depth of 1.7 m below grade. The clay deposit is about 12.7 m thick, mottled brown and grey in color to a depth of about 8 m below which it is grey. It is moist, has a stiff consistency to a depth of about 10 m below which the clay is firm. The clay is of high plasticity and it contains trace silt inclusions. The moisture contents of the clay range from about 45 to 65 percent.

The undrained shear strength of the clay was measured using Torvane, penetrometer and unconfined compressive strength tests. The clay is stiff to a depth of about 10 m with undrained shear strengths ranging from about 35 to 70 kPa. Below 10 m, the consistency of the clay becomes firm with undrained shear strengths varying between about 25 and 45 kPa. The bulk unit weight of the clay is about 17 kN/m³.

Silt (Till)

Glacial silt till was encountered at a depth of 14.3 m. The till in the Winnipeg area is known to be a heterogeneous mixture of sand, gravel, cobble and boulder size materials in a clay and/or silt matrix. The till encountered in the test hole is a grey silt till containing trace amounts of sand and gravel. The moisture content of the till encountered is around 10 percent. Auger refusal occurred a depth of 14.9 m.

Test Hole Stability and Groundwater Conditions

A minor amount of seepage was observed from the silt layer. No sloughing conditions were observed in the test hole. The groundwater conditions should be expected to vary seasonally, from year to year and possibly as a result of construction activities.

TRANSCONA CENTENNIAL POOL REDEVELOPMENT – PHASE 1B 3

4) Discussion and Recommendations The subsurface conditions at this site are suitable for cast-in-place concrete friction piles. Cast-In-Place Concrete Friction Piles Cast-in-place concrete friction piles can be designed in accordance to the current Manitoba Building Code (i.e. NBC 2010) using the service limit state (SLS) shaft adhesion values provided in Table 1 below. For the ultimate limit state (ULS) case, the piles can be designed with the factored shaft adhesion values and the factored end bearing pressures provided in Table 1. A resistance factor of 0.4 was used to calculate the factored ULS design values. Under the SLS loads, pile settlements are expected to be around 6 mm with differential settlements between piles around 3 to 6 mm.

Table 1: Design Parameters for CIP Concrete Friction Piles

Depth Below Existing Site Grade

(m)

SLS Shaft Adhesion

(kPa)

Factored ULS Shaft

Adhesion End Bearing

(kPa) (kPa) 0 to 3 (see Note 1) 0 0 0

3 to 10.5 16.5 20.0 180 10.5 to 13 11.5 14.0 125

Note 1: When determining effective pile lengths, the upper 3 m of the pile shaft below existing site grade or 1.5 m below crawl space level, whichever is deeper, should be ignored to account for the presence of fill materials, silt layers and the potential for soil shrinkage away from the pile.

The pile length should be limited to 13 m below existing site grade to avoid drilling into the glacial till layer. Piles should have a minimum diameter of 400 mm, a minimum length of 6 m and a minimum spacing of 3 pile diameters on centre. Where this spacing cannot be achieved DRI should be contacted for additional input. Small pile groups (maximum of 3 piles) can be considered for moderately high column loads.

The manhole / sump pit excavation should have clear distance of at least 1.2 m to the nearest pile location. The manhole excavation should not be made until the manhole is ready to install and once installed the excavation should be promptly backfilled.

Concrete should be placed as soon as possible after each pile hole is completed. Temporary steel sleeves should be on site and used where sloughing/caving of the pile borings occur and/or if groundwater seepage is encountered.

Piles that are subjected to freezing conditions must be protected from potential frost heave effects by using minimum pile lengths of 7.6 m and installing full length reinforcement. The use of flat lying rigid insulation, such as Styrofoam HI, can also be used to minimize frost penetration into the soil around the piles if the minimum pile length cannot be achieved. A greased, polyethylene wrapped sonotube can be placed around the upper 1.8 m of the pile shaft to act as a bond breaker and provide additional protection against frost heave. A void separation of at least 150 mm should be provided under grade beams and pile caps.

TRANSCONA CENTENNIAL POOL REDEVELOPMENT – PHASE 1B 4

Floor Slabs We recommend that a structural floor slab over a void space be considered for the building, due to the presence of high plastic (i.e. expansive) clay soils at this site. A void separation between the structural floor slab and underlying soil should be at least 150 mm thick. A vapour barrier should be provided below the floor slab. Structural floor slabs will minimize the potential for movement due to heave or swelling of the underlying clay soils. It is possible that the total amount of heave and swelling could be on the order of 100 mm in the long term. A major factor impacting the magnitude of floor slab movements, which will ultimately occur, are the climatic effects during construction which might impact changes in the sub-soil moisture conditions. For this reason, it is not possible to assess the amount of heave which will occur with any degree of accuracy. If floor slabs on grade are considered, they must be expected to undergo movements as a result of volumetric changes of the underlying clay soils which are known to be expansive in nature. Floor slab movements are generally expected to be around 25 to 50 mm but it is possible that the long term floor movements could be on the order of 100 mm. If used, some maintenance / repair of a slab on grade floor may be required in the future. If used, slab-on-grade floors could be isolated from fixed building components (e.g. walls / grade beams) to allow for some floor slab movements to occur without affecting the structure. A vapour barrier below the floor slab should be provided to minimize the potential for long term moisture changes within the underlying clay soils. The floor slab should not be placed against frozen soil. The floor slab should be supported on at least 200 mm of compacted granular base placed on a prepared sub-grade. The granular base should be a 19 mm down crushed limestone material that meets the material selection and construction requirements in the City of Winnipeg’s Standard Construction Specifications. Fill, loose and deleterious materials should be stripped from the sub-grade surface prior to preparation. The sub-grade should be uniformly compacted to at least 95 of the standard Proctor maximum dry density before the granular sub-base material is placed. Below Grade Walls Basement walls, should be designed to resist lateral earth pressures that are derived on the basis of the following conventional relationship which produces a triangular pressure distribution:

P = K γ D

where P = lateral earth pressure at depth D (kPa) K = earth pressure coefficient (0.5) γ = soil/backfill unit weight 17.3 (kN/m3) D = depth from surface to point of pressure calculation (m) The base of the wall should be provided with a filter-protected positive drainage system to prevent the buildup of hydrostatic pressure against the wall. The basement walls should be backfilled with a clean pit run sand and gravel with a maximum particle size of 75 mm. The upper 0.6 m (minimum) of the backfill around the basement walls should be a compacted clay to act as a barrier to prevent infiltration of water

TRANSCONA CENTENNIAL POOL REDEVELOPMENT – PHASE 1B 5

into the granular backfill. The clay should be compacted to 90 to 92 percent of the standard Proctor maximum dry density. Excavations All excavation work should be completed by the Contractor in accordance with the current Manitoba Workplace Health and Safety Regulations to suit the planned and expected construction activities and schedule. Other The potential for sulphate attack in Winnipeg is considered to be severe (Exposure Class S-2). All concrete in contact with soil should be made with sulphate resistance cement in accordance with the Manitoba Building Code and relevant CSA standards. Positive drainage should be provided away from all structures at gradients of at least 2 percent.

DYREGROV ROBINSON INC. 1 Terms and Symbols

EXPLANATION OF TERMS & SYMBOLS

Description TH Log Symbols

USCS Classification

Laboratory Classification Criteria

Fines (%) Grading Plasticity Notes

CO

AR

SE

GR

AIN

ED

SO

ILS

GRAVELS (More than

50% of coarse

fraction of gravel size)

CLEAN GRAVELS (Little or no

fines)

Well graded gravels, sandy gravels, with little

or no fines GW 0-5 CU > 4

1 < CC < 3

Dual symbols if 5-12% fines.

Dual symbols if above “A” line and

4<WP<7

10

60

D

DCU

6010

2

30

xDD

DCC

Poorly graded gravels, sandy gravels, with little

or no fines GP 0-5

Not satisfying GW

requirements

DIRTY GRAVELS (With some

fines)

Silty gravels, silty sandy gravels

GM > 12 Atterberg limits below “A” line

or WP<4

Clayey gravels, clayey sandy gravels

GC > 12 Atterberg limits above “A” line

or WP<7

SANDS (More than

50% of coarse

fraction of sand size)

CLEAN SANDS

(Little or no fines)

Well graded sands, gravelly sands, with little

or no fines SW 0-5 CU > 6

1 < CC < 3

Poorly graded sands, gravelly sands, with little

or no fines SP 0-5

Not satisfying SW

requirements

DIRTY SANDS

(With some fines)

Silty sands, sand-silt mixtures

SM > 12

Atterberg limits below “A” line

or WP<4

Clayey sands, sand-clay mixtures

SC > 12

Atterberg limits above “A” line

or WP<7

FIN

E G

RA

INE

D S

OIL

S

SILTS (Below ‘A’

line negligible organic content)

WL<50 Inorganic silts, silty or clayey fine sands, with

slight plasticity ML

Classification is Based upon

Plasticity Chart

WL>50 Inorganic silts of high plasticity

MH

CLAYS (Above ‘A’

line negligible organic content)

WL<30 Inorganic clays, silty clays, sandy clays of

low plasticity, lean clays CL

30<WL<50 Inorganic clays and silty

clays of medium plasticity

CI

WL>50 Inorganic clays of high plasticity, fat clays

CH

ORGANIC SILTS & CLAYS

(Below ‘A’ line)

WL<50 Organic silts and

organic silty clays of low plasticity

OL

WL>50 Organic clays of high plasticity

OH

HIGHLY ORGANIC SOILS Peat and other highly

organic soils Pt Von Post

Classification Limit Strong colour or odour, and often

fibrous texture

Asphalt

Glacial Till

Bedrock (Igneous)

DYREGROV ROBINSON INC. CONSULTING GEOTECHNICAL ENGINEERS

Concrete

Clay Shale

Bedrock (Limestone)

Fill

Bedrock

(Undifferentiated)

DYREGROV ROBINSON INC. 2 Terms and Symbols

FRACTION PARTICLE SIZE

(mm) RELATIVE PROPORTIONS

(by weight) Min. Max.

Boulders >300 Percent Descriptor Cobbles 75 300 >35% main fraction

Gravel Coarse 19 75 35 - 50 “and” Fine 4.75 19

Sand

Coarse 2.0 4.75 20 – 35

Adjective e.g. silty, clayey Medium 0.425 2.0

Fine 0.075 0.425 10 – 20 “some”

Silt (non-plastic) or Clay (plastic) < 0.075 mm 1 - 10 “trace”

Soil Classification Example

Clay 50% (main fraction), Silt 25%, Sand 17%, Gravel 8%

Clay – silty, some sand, trace gravel

TERMS and SYMBOLS

Laboratory and field tests are identified as follows:

Unconfined Comp.: undrained shear strength (kPa or psf) derived from unconfined compression testing.

Torvane: undrained shear strength (kPa or psf) measured using a Torvane

Pocket Pen.: undrained shear strength (kPa or psf) measured using a pocket penetrometer.

Unit Weight bulk unit weight of soil or rock (kN/m3 or pcf).

SPT – N Standard Penetration Test: The number of blows (N) required to drive a 51 mm O.D. split barrel sampler

300 mm into the soil using a 63.5 kg hammer with a free fall drop height of 760 mm.

DCPT Dynamic Cone Penetration Test. The number of blows (N) required to drive a 50 mm diameter cone 300 mm

into the soil using a 63.5 kg hammer with a free fall drop height of 760 mm.

M/C insitu soil moisture content in percent

PL Plastic limit, moisture content in percent

LL Liquid limit, moisture content in percent

The undrained shear strength (Su) of cohesive soil The SPT - N of non-cohesive soil is related to is related to its consistency as follows: compactness condition as follows:

Su (kPa) Su (psf) CONSISTENCY

<12 250 very soft 12 – 25 250 – 525 soft 25 – 50 525 – 1050 firm

50 – 100 1050 – 2100 stiff 100 – 200 2100 – 4200 very stiff

200 4200 hard References:

ASTM D2487 – Classification of Soils For Engineering Purposes (Unified Soil Classification System) Canadian Foundation Engineering Manual, 4th Edition, Canadian Geotechnical Society, 2006

N – Blows / 300 mm COMPACTNESS

0 - 4 very loose 4 - 10 loose

10 - 30 compact 30 - 50 dense

50 + very dense

G1

G2

G3

T4

G5

T6

G7

T8

G9

G10

G11

CLAY - silty, trace organics- black- stiff, moist- high plasticity, trace silt inclusions

SILT - trace clay, brown, loose, wetCLAY - silty- mottled brown and grey- stiff, moist- high plasticity, trace silt inclusions

- grey, wet, firm below 10 m- trace till inclusions, trace sand, trace gravel

SILT (TILL) - trace sand, trace gravel- grey, compact to dense, moist

END OF TEST HOLE AT 14.9 m IN SILT(TILL)(AUGER REFUSAL)Notes:1. Minor seepage observed from silt layer1.5 to 1.6 m.2. No sloughing observed.3. Test hole backfilled with bentonite chips and auger cuttings.

TESTHOLE NO: 1PROJECT NO.: 153928ELEVATION (m):

BULK

PROJECT: Transcona Pool - Phase 1BLOCATION: 24 m west and 11 m south from south west corner of existing swimming poolCONTRACTOR: Paddock Drilling Ltd.

CORE

SLOUGH GROUT

CLIENT: City of Winnipeg

SHELBY TUBE

CUTTINGSGRAVELBACKFILL TYPE SANDBENTONITE

SAMPLE TYPE GRAB SPLIT SPOON

ELE

VA

TIO

N (

m)

LOGGED BY: CRREVIEWED BY: GRPROJECT ENGINEER: Gil Robinson

COMPLETION DEPTH: 14.94 mCOMPLETION DATE: 12/3/15

NO RECOVERYD

EP

TH

(m

)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

METHOD: RM - 30 drill rig, 125 mm SS augers

BH

GE

OT

EC

H P

LOT

S -

NE

W A

LT1

153

928

_CO

W_T

RA

NS

CO

NA

PO

OL

PH

AS

E 1

B.G

PJ

DA

TA

TE

MP

LAT

E -

AU

GU

ST

2, 2

013.

GD

T

17/1

2/15

Consulting Geotechnical EngineersDYREGROV ROBINSON INC.

.

SA

MP

LE #

SA

MP

LE T

YP

E

SOIL DESCRIPTION

SO

IL S

YM

BO

L SPT N blows/300mm

10 20 30 40 50 60 70

Unit Weight kN/m³

12 14 16 18 20 22 24

10 20 30 40 50 60 70

LL PLM/C (%) Pocket Pen. (Su) kPa

10 20 30 40 50 60 70

Unconfined Comp. (Su) kPa

10 20 30 40 50 60 70

Torvane (Su) kPa

10 20 30 40 50 60 70